(a) Technical Field
Embodiments relate to a soft start circuit and a buck converter including the same.
(b) Description of the Related Art
When a buck converter has an output voltage higher than an input voltage, a switch of the buck converter is not switched and thus an current does not flow through an inductor of the buck converter.
Generally, the buck converter also uses a reference signal that constantly increases for a soft start. When an output voltage is higher than an input voltage, a difference between a feedback voltage corresponding to the output voltage and a voltage of the reference signal increases. A control voltage for controlling a switching operation is determined according to the difference between the feedback voltage and the reference signal voltage. In this case, the control voltage may be saturated due to a sudden increase in the difference between the two voltages when the output voltage is higher than the input voltage during the soft start time period.
Then, an overshoot occurs in the output voltage, and a time taken to reach a steady state after the soft start increases.